Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division—Code Division Multiple Access (TD-CDMA), and Time Division—Synchronous Code Division Multiple Access (TD-SCDMA). UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
Recently, heterogeneous networks have been an area of intense interest due to their promise of improved wireless coverage in otherwise difficult-to-cover areas like train stations, tunnels, office buildings, and homes. A heterogeneous network may include conventional high-power nodes, sometimes called macrocells, as well as various low-power nodes such as microcells, picocells, and femtocells, with varying capacities, coverage areas, and power capabilities. However, with such a deployment where different base stations have different power levels, a number of issues can arise relating to interference between the different base stations, or between user equipment served by one or the other type of base station. Additionally, due to the varying power capabilities of the different types of base stations, when one type of base station sends a power control command to a user equipment, e.g., to reduce interference from its uplink transmissions, this can adversely affect reception of those transmissions by another type of base station.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.